The velcro VBSN is a M/L which is a medium/large or a medium/long - typically it's for babies who are just growing out of medium diapers. The other 2 VBSN diapers (the snapping ones) are both a size large - I had these made with crossover snaps so I could use them earlier. I had no problem using these diapers the same time my sons were in medium diapers - and I never needed the crossover snaps so they might fit even earlier. My sons never really needed large diapers so I can't say how big of a child these will fit - but we never used the largest snap settings and they never got to tight or too small on my boys.